315 research outputs found
Forces on a spherical conducting particle in E x B fields
The forces acting on a spherical conducting particle in a transversely flowing magnetized plasma are calculated in the entire range of magnetization and Debye length, using the particle code SCEPTIC3D (Patacchini and Hutchinson 2010 Plasma Phys. Control. Fusion 52 035005, 2011 Plasma Phys. Control. Fusion 53 025005). In short Debye length (i.e. high density) plasmas, both the ion-drag and Lorentz force arising from currents circulating inside the dust show strong components antiparallel to the convective electric field, suggesting that a free dust particle should gyrate faster than what predicted by its Larmor frequency. In intermediate to large Debye length conditions, by a downstream depletion effect already reported in unmagnetized strongly collisional regimes, the ion-drag in the direction of transverse flow can become negative. The internal Lorentz force, however, remains in the flow direction, and large enough in magnitude so that no spontaneous dust motion should occur.National Science Foundation (U.S.)United States. Dept. of Energy (grant DE-FG02-06ER54891
Spherical probes at ion saturation in E Ă— B fields
The ion saturation current to a spherical probe in the entire range of ion
magnetization is computed with SCEPTIC3D, a newthree-dimensional version
of the kinetic code SCEPTIC designed to study transverse plasma flows. Results
are compared with prior two-dimensional calculations valid in the magneticfree
regime (Hutchinson 2002 Plasma Phys. Control. Fusion 44 1953), and
with recent semi-analytic solutions to the strongly magnetized transverse Mach
probe problem (Patacchini and Hutchinson 2009 Phys. Rev. E 80 036403).
At intermediate magnetization (ion Larmor radius close to the probe radius)
the plasma density profiles show a complex three-dimensional structure that
SCEPTIC3D can fully resolve, and, contrary to intuition, the ion current peaks
provided the ion temperature is low enough. Our results are conveniently
condensed in a single factor M[subscript c], function of ion temperature and magnetic
field only, providing the theoretical calibration for a transverse Mach probe
with four electrodes placed at 45â—¦ to the magnetic field in a plane of flow and
magnetic field
An urban sprawl index based on multivariate and Bayesian factor analysis with application at the municipality level in Valencia
[EN] Urban sprawl is now a common and threatening phenomenon in Europe, severely affecting
environmental and economic sustainability. An analytical characterization and measurement of
urban sprawl are required to gain a better understanding of the phenomenon and to propose the
possible solutions. Traditional factor analysis techniques, especially Principal Component Analysis
and Factor Analysis, have been commonly used. In this paper, we additionally test Independent
Component Analysis with the aim to obtain a multidimensional characterization of the sprawl
phenomenon. We also use Bayesian Factor Analysis to obtain a single (unidimensional) measuring
index of sprawl, which also allows us to obtain the uncertainty of the inferred index, in contrast to
traditional approaches. All these techniques have been applied to study the phenomenon of urban
sprawl at the municipality level in Valencia, Spain using a wide set of variables related to the
characteristics and patterns of urban land use.Gielen, E.; Riutort-Mayol, G.; Palencia JimĂ©nez, JS.; Cantarino-MartĂ, I. (2017). An urban sprawl index based on multivariate and Bayesian factor analysis with application at the municipality level in Valencia. Environment and Planning B Planning and Design. 1-27. doi:10.1177/2399808317690148S12
PP272—Migraine and parthenolide inhibition of transient receptor potential ankyrin 1
2013 e103 emerged as a major complication of bortezomib therapy, which usually appears in the first courses of therapy with a number of sensory and painful symptoms, including reduced threshold to mechanical and cold stimuli. No satisfactory explanation or effective treatment exists for bortezomib-evoked CIPN. Patients (or Materials) and Methods: In this study, we evaluated whether TRPA1 acted as a critical mediator of CIPN by bortezomib or oxaliplatin in a mouse model system. Results: Our data demonstrated that CIPN hypersensitivity phenotype that was stably established by bortezomib could be transiently reverted by systemic or local treatment with the TRPA1 antagonist HC-030031. A similar effect was produced by the oxidative stress scavenger α -lipoic acid. Notably, the CIPN phenotype was abolished completely in mice that were genetically deficient in TRPA1, highlighting its essential role. Administration of bortezomib or oxaliplatin, which also elicits TRPA1-dependent hypersensitivity, produced a rapid, transient increase in plasma of carboxy-methyllysine, a byproduct of oxidative stress. Short-term systemic treatment with either HC-030031 or α -lipoic acid could completely prevent hypersensitivity if administered before the cytotoxic drug. Conclusion: Our findings highlight a key role for early activation/ sensitization of TRPA1 by oxidative stress by-products in producing CIPN. Furthermore, they suggest prevention strategies for CIPN in patients through the use of early, short-term treatments with TRPA1 antagonists. Disclosure of Interest: None declared
Schwann cell TRPA1 mediates neuroinflammation that sustains macrophage-dependent neuropathic pain in mice
It is known that transient receptor potential ankyrin 1 (TRPA1) channels, expressed by nociceptors, contribute to neuropathic pain. Here we show that TRPA1 is also expressed in Schwann cells. We found that in mice with partial sciatic nerve ligation, TRPA1 silencing in nociceptors attenuated mechanical allodynia, without affecting macrophage infiltration and oxidative stress, whereas TRPA1 silencing in Schwann cells reduced both allodynia and neuroinflammation. Activation of Schwann cell TRPA1 evoked NADPH oxidase 1 (NOX1)-dependent H2O2 release, and silencing or blocking Schwann cell NOX1 attenuated nerve injury-induced macrophage infiltration, oxidative stress and allodynia. Furthermore, the NOX2-dependent oxidative burst, produced by macrophages recruited to the perineural space activated the TRPA1-NOX1 pathway in Schwann cells, but not TRPA1 in nociceptors. Schwann cell TRPA1 generates a spatially constrained gradient of oxidative stress, which maintains macrophage infiltration to the injured nerve, and sends paracrine signals to activate TRPA1 of ensheathed nociceptors to sustain mechanical allodynia
Short-Run Regional Forecasts: Spatial Models through Varying Cross-Sectional and Temporal Dimensions
In any economic analysis, regions or municipalities should not be regarded as isolated spatial units, but rather as highly interrelated small open economies. These spatial interrelations must be considered also when the aim is to forecast economic variables. For example, policy makers need accurate forecasts of the unemployment evolution in order to design short- or long-run local welfare policies. These predictions should then consider the spatial interrelations and dynamics of regional unemployment. In addition, a number of papers have demonstrated the improvement in the reliability of long-run forecasts when spatial dependence is accounted for. We estimate a heterogeneouscoefficients dynamic panel model employing a spatial filter in order to account for spatial heterogeneity and/or spatial autocorrelation in both the levels and the dynamics of unemployment, as well as a spatial vector-autoregressive (SVAR) model. We compare the short-run forecasting performance of these methods, and in particular, we carry out a sensitivity analysis in order to investigate if different number and size of the administrative regions influence their relative forecasting performance. We compute short-run unemployment forecasts in two countries with different administrative territorial divisions and data frequency: Switzerland (26 regions, monthly data for 34 years) and Spain (47 regions, quarterly data for 32 years)
- …